1
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Gremillion AJ, Ross J, Yu X, Ishtaweera P, Anwander R, Autschbach J, Baker GA, Kelley SP, Walensky JR. Facile Oxidation of Ce(III) to Ce(IV) Using Cu(I) Salts. Inorg Chem 2024; 63:9602-9609. [PMID: 38507258 DOI: 10.1021/acs.inorgchem.3c04337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2024]
Abstract
The synthesis, luminescence, and electrochemical properties of the Ce(III) compound, [(C5Me5)2(2,6-iPr2C6H3O)Ce(THF)], 1, were investigated. Based on the electrochemical data, treatment of 1 with CuX (X = Cl, Br, I) results in the formation of the corresponding Ce(IV) complexes, [(C5Me5)2(2,6-iPr2C6H3O)Ce(X)]. Each complex has been characterized using NMR, IR, and UV-vis spectroscopy as well as structurally determined using X-ray crystallography. Additionally, the treatment of [(C5Me5)2(2,6-iPr2C6H3O)Ce(Br)] with AgF results in the formation of the putative [(C5Me5)2(2,6-iPr2C6H3O)Ce(F)]. The electronic structure of these Ce(IV)-X complexes was investigated by bond analyses and the Ce(IV)-F moiety using quantum chemistry NMR calculations.
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Affiliation(s)
- Alexander J Gremillion
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - Jason Ross
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - Xiaojuan Yu
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260, United States
| | - Piyuni Ishtaweera
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - Reiner Anwander
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, 72076 Tübingen, Germany
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260, United States
| | - Gary A Baker
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - Steven P Kelley
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - Justin R Walensky
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
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2
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Mahieu N, Piątkowski J, Simler T, Nocton G. Back to the future of organolanthanide chemistry. Chem Sci 2023; 14:443-457. [PMID: 36741512 PMCID: PMC9848160 DOI: 10.1039/d2sc05976b] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 11/29/2022] [Indexed: 12/02/2022] Open
Abstract
At the dawn of the development of structural organometallic chemistry, soon after the discovery of ferrocene, the description of the LnCp3 complexes, featuring large and mostly trivalent lanthanide ions, was rather original and sparked curiosity. Yet, the interest in these new architectures rapidly dwindled due to the electrostatic nature of the bonding between π-aromatic ligands and 4f-elements. Almost 70 years later, it is interesting to focus on how the discipline has evolved in various directions with the reports of multiple catalytic reactivities, remarkable potential in small molecule activation, and the development of rich redox chemistry. Aside from chemical reactivity, a better understanding of their singular electronic nature - not precisely as simplistic as anticipated - has been crucial for developing tailored compounds with adapted magnetic anisotropy or high fluorescence properties that have witnessed significant popularity in recent years. Future developments shall greatly benefit from the detailed reactivity, structural and physical chemistry studies, particularly in photochemistry, electro- or photoelectrocatalysis of inert small molecules, and manipulating the spins' coherence in quantum technology.
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Affiliation(s)
- Nolwenn Mahieu
- LCM, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, Route de Saclay91120 PalaiseauFrance
| | - Jakub Piątkowski
- LCM, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, Route de Saclay91120 PalaiseauFrance
| | - Thomas Simler
- LCM, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, Route de Saclay91120 PalaiseauFrance
| | - Grégory Nocton
- LCM, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, Route de Saclay91120 PalaiseauFrance
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3
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Abstract
The number of rare earth (RE) starting materials used in synthesis is staggering, ranging from simple binary metal-halide salts to borohydrides and "designer reagents" such as alkyl and organoaluminate complexes. This review collates the most important starting materials used in RE synthetic chemistry, including essential information on their preparations and uses in modern synthetic methodologies. The review is divided by starting material category and supporting ligands (i.e., metals as synthetic precursors, halides, borohydrides, nitrogen donors, oxygen donors, triflates, and organometallic reagents), and in each section relevant synthetic methodologies and applications are discussed.
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Affiliation(s)
- Fabrizio Ortu
- School of Chemistry, University of Leicester, LE1 7RH Leicester, U.K.
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4
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Hirneise L, Maichle-Mössmer C, Anwander R. Pentamethylcyclopentadienyl Complexes of Cerium(IV): Synthesis, Reactivity, and Electrochemistry. Inorg Chem 2021; 60:18211-18224. [PMID: 34779192 DOI: 10.1021/acs.inorgchem.1c02851] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Treatment of Cp*2CeCl2K(THF) with alkali-metal alkoxides and siloxides in the presence of hexachloroethane generates the monomeric bis(pentamethylcyclopentadienyl) cerium(IV) complexes Cp*2Ce(OR)2 (Cp* = C5Me5; R = Et, iPr, CH2tBu, tBu, SiMe3, or SiPh3). Large substituents R trigger ligand scrambling to half-sandwich complexes Cp*Ce(OR)3, which could be isolated for R = tBu and SiPh3. Similar reactions with sodium aryloxide NaOAr (OAr = OC6H3iPr2-2,6) led to Cp*2Ce(OAr)Cl. Treatment of tris(cyclopentadienyl) complexes CpR3CeCl (CpH = Cp = C5H5; CpMe = C5H4Me) with NaOAr afforded CpMe2Ce(OAr)2 and Cp3Ce(OAr). The cerium(IV) complexes display a pseudotetrahedral geometry in the solid state. Cyclic voltammetry revealed mostly chemically reversible as well as electrochemically quasi-reversible redox processes with potentials ranging from -0.84 to -1.61 V versus Fc/Fc+. Switching from sandwich to half-sandwich complexes decreased the electrochemical potentials drastically, showing better stabilization of the cerium(IV) center in the case of Cp*Ce(OR)3 than in the case of Cp*2Ce(OR)2. Enhanced stabilization of the cerium +IV oxidation state could be further demonstrated in the series alkoxy > siloxy > aryloxy as well as C5Me5 > C5HMe4.
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Affiliation(s)
- Lars Hirneise
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Cäcilia Maichle-Mössmer
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Reiner Anwander
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
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5
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Hirneise L, Langmann J, Zitzer G, Ude L, Maichle-Mössmer C, Scherer W, Speiser B, Anwander R. Tuning Organocerium Electrochemical Potentials by Extending Tris(cyclopentadienyl) Scaffolds with Terminal Halogenido, Siloxy, and Alkoxy Ligands. Organometallics 2021. [DOI: 10.1021/acs.organomet.1c00276] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Lars Hirneise
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Jan Langmann
- Institut für Physik, Universität Augsburg, Universitätsstraße 1, 86159 Augsburg, Germany
| | - Georg Zitzer
- Institut für Organische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Lukas Ude
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Cäcilia Maichle-Mössmer
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Wolfgang Scherer
- Institut für Physik, Universität Augsburg, Universitätsstraße 1, 86159 Augsburg, Germany
| | - Bernd Speiser
- Institut für Organische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Reiner Anwander
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
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6
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Panetti GB, Sergentu DC, Gau MR, Carroll PJ, Autschbach J, Walsh PJ, Schelter EJ. Isolation and characterization of a covalent Ce IV-Aryl complex with an anomalous 13C chemical shift. Nat Commun 2021; 12:1713. [PMID: 33731719 PMCID: PMC7969749 DOI: 10.1038/s41467-021-21766-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 02/02/2021] [Indexed: 12/13/2022] Open
Abstract
The synthesis of bona fide organometallic CeIV complexes is a formidable challenge given the typically oxidizing properties of the CeIV cation and reducing tendencies of carbanions. Herein, we report a pair of compounds comprising a CeIV - Caryl bond [Li(THF)4][CeIV(κ2-ortho-oxa)(MBP)2] (3-THF) and [Li(DME)3][CeIV(κ2-ortho-oxa)(MBP)2] (3-DME), ortho-oxa = dihydro-dimethyl-2-[4-(trifluoromethyl)phenyl]-oxazolide, MBP2- = 2,2'-methylenebis(6-tert-butyl-4-methylphenolate), which exhibit CeIV - Caryl bond lengths of 2.571(7) - 2.5806(19) Å and strongly-deshielded, CeIV - Cipso 13C{1H} NMR resonances at 255.6 ppm. Computational analyses reveal the Ce contribution to the CeIV - Caryl bond of 3-THF is ~12%, indicating appreciable metal-ligand covalency. Computations also reproduce the characteristic 13C{1H} resonance, and show a strong influence from spin-orbit coupling (SOC) effects on the chemical shift. The results demonstrate that SOC-driven deshielding is present for CeIV - Cipso 13C{1H} resonances and not just for diamagnetic actinide compounds.
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Affiliation(s)
- Grace B Panetti
- Roy and Diana Vagelos Laboratories Department of Chemistry, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Michael R Gau
- Roy and Diana Vagelos Laboratories Department of Chemistry, University of Pennsylvania, Philadelphia, PA, USA
| | - Patrick J Carroll
- Roy and Diana Vagelos Laboratories Department of Chemistry, University of Pennsylvania, Philadelphia, PA, USA
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY, USA.
| | - Patrick J Walsh
- Roy and Diana Vagelos Laboratories Department of Chemistry, University of Pennsylvania, Philadelphia, PA, USA.
| | - Eric J Schelter
- Roy and Diana Vagelos Laboratories Department of Chemistry, University of Pennsylvania, Philadelphia, PA, USA.
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7
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Anwander R, Dolg M, Edelmann FT. The difficult search for organocerium(iv) compounds. Chem Soc Rev 2018; 46:6697-6709. [PMID: 28913523 DOI: 10.1039/c7cs00147a] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
This Tutorial Review provides an overview of the historic and current development of the organometallic chemistry of cerium in its oxidation state 4+. Among the tetravalent lanthanide ions, only Ce4+ forms stable coordination compounds (e.g. (NH4)2[Ce(NO3)6]). Important fields of applications for cerium(iv) compounds include organic synthesis, bioinorganic chemistry, materials science, and industrial catalysis. In sharp contrast, organometallic cerium(iv) compounds are still exceedingly rare. The history of organocerium(iv) compounds is an exciting story of ups and downs. The so-called cerocene (= bis(η8-cyclooctatetraenyl) cerium) has been known since 1976. Other early reports e.g. about Cp4Ce (Cp = η5-cyclopentadienyl), were later disproven. However, significant progress in this field has been made in recent years through the use of carefully designed ligands and more sophisticated synthesis protocols. Taking the case of organocerium(iv) chemistry, this Tutorial Review also tries to exemplarily show how difficult synthetic and theoretical problems can eventually be solved through newly designed synthesis strategies (e.g. as accomplished for cyclopentadienyl and carbene derivatives) and a rewarding collaboration between synthetic and theoretical chemists (cf. the cerocene problem).
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Affiliation(s)
- Reiner Anwander
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, D-72076 Tübingen, Germany
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8
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Raeder J, Reiners M, Baumgarten R, Münster K, Baabe D, Freytag M, Jones PG, Walter MD. Synthesis and molecular structure of pentadienyl complexes of the rare-earth metals. Dalton Trans 2018; 47:14468-14482. [DOI: 10.1039/c8dt03123a] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
In combination with small and difficult to reduce rare-earth metals pdl′ undergoes CH-bond activations instead of sterically induced reductions to form dimeric complexes with a unique bridging six-membered metallacycle as the central structural motif.
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Affiliation(s)
- Jan Raeder
- Technische Universität Braunschweig
- Institut für Anorganische und Analytische Chemie
- 38106 Braunschweig
- Germany
| | - Matthias Reiners
- Technische Universität Braunschweig
- Institut für Anorganische und Analytische Chemie
- 38106 Braunschweig
- Germany
| | - Robert Baumgarten
- Technische Universität Braunschweig
- Institut für Anorganische und Analytische Chemie
- 38106 Braunschweig
- Germany
| | - Katharina Münster
- Technische Universität Braunschweig
- Institut für Anorganische und Analytische Chemie
- 38106 Braunschweig
- Germany
| | - Dirk Baabe
- Technische Universität Braunschweig
- Institut für Anorganische und Analytische Chemie
- 38106 Braunschweig
- Germany
| | - Matthias Freytag
- Technische Universität Braunschweig
- Institut für Anorganische und Analytische Chemie
- 38106 Braunschweig
- Germany
| | - Peter G. Jones
- Technische Universität Braunschweig
- Institut für Anorganische und Analytische Chemie
- 38106 Braunschweig
- Germany
| | - Marc D. Walter
- Technische Universität Braunschweig
- Institut für Anorganische und Analytische Chemie
- 38106 Braunschweig
- Germany
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9
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10
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Schneider D, Harmgarth N, Edelmann FT, Anwander R. Ceric Cyclopentadienides Bearing Alkoxy, Aryloxy, Chlorido, or Iodido Co-Ligands. Chemistry 2017; 23:12243-12252. [PMID: 28334455 DOI: 10.1002/chem.201700743] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Indexed: 12/23/2022]
Abstract
A series of heteroleptic tris(cyclopentadienyl) CeIV complexes has been isolated and crystallographically characterized, revealing the broad accessibility of such organocerium(IV) compounds. The oxidation of complexes CpMe3 Ce(thf) and Cp'3 Ce(thf) (CpMe =C5 H4 Me, Cp'=C5 H4 SiMe3 ), bearing monosubstituted electron-poor cyclopentadienyl ligands, with 0.5 equivalents of 1,4-benzoquinone or C2 Cl6 gave the cerium(IV) hydroquinolate complexes CpMe3 Ce(OC6 H4 O)CeCpMe3 and Cp'3 Ce(OC6 H4 O)CeCp'3 , or the chloride complexes CpMe3 CeCl and Cp'3 CeCl, respectively; the iodide complex Cp'3 CeI was obtained from the reaction of Cp'3 Ce(thf) with elemental iodine. The behavior of Cp'3 CeCl in salt metathesis protocols employing alkali metal amides or alkyl, alkoxide, and aryloxide reagents was investigated, which gave rise to the robust and isolable cerium(IV) alkoxide Cp'3 Ce(OtBu). Trivalent [Cp'2 CeCl]2 was synthesized by AlMe4 →Cl exchange utilizing Cp'2 Ce(AlMe4 ) and AlMe2 Cl. The reactivity of [Cp'2 CeCl]2 towards the oxidants Ph3 CCl, C2 Cl6 , 1,4-benzoquinone, and I2 has been assessed, and has provided useful information on CeIII /CeIV redox deactivation pathways. In addition to X-ray structure analysis, all the complexes were characterized by NMR, DRIFT (diffuse reflectance IR Fourier transform), and UV/Vis spectroscopy as well as elemental analysis. The tetravalent compounds were further analyzed for their magnetic susceptibility by using Evans' method.
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Affiliation(s)
- David Schneider
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
| | - Nicole Harmgarth
- Institut für Chemie, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106, Magdeburg, Germany
| | - Frank T Edelmann
- Institut für Chemie, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106, Magdeburg, Germany
| | - Reiner Anwander
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
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11
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Schneider D, Anwander R. Pentamethylcyclopentadienyl‐Supported Cerocene(III) Complexes. Eur J Inorg Chem 2017. [DOI: 10.1002/ejic.201601404] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- David Schneider
- Institut für Anorganische Chemie Eberhard Karls Universität Tübingen Auf der Morgenstelle 18 72076 Tübingen Germany
| | - Reiner Anwander
- Institut für Anorganische Chemie Eberhard Karls Universität Tübingen Auf der Morgenstelle 18 72076 Tübingen Germany
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12
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Friedrich J, Maichle-Mössmer C, Anwander R. Synthesis and derivatisation of ceric tris(tert-butoxy)siloxides. Chem Commun (Camb) 2017; 53:12044-12047. [DOI: 10.1039/c7cc06499c] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Heteroleptic ceric Ce[OSi(OtBu)3]3Cl(thf) is straightforwardly obtained from cerous Ce[OSi(OtBu)3]3(thf)2 and trityl chloride and gives access to the terminal siloxy/methoxy derivative Ce[OSi(OtBu)3]3(OCH3)(thf)2.
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Affiliation(s)
- Jochen Friedrich
- Institut für Anorganische Chemie Universität Tübingen
- Auf der Morgenstelle 18
- 72076 Tübingen
- Germany
| | - Cäcilia Maichle-Mössmer
- Institut für Anorganische Chemie Universität Tübingen
- Auf der Morgenstelle 18
- 72076 Tübingen
- Germany
| | - Reiner Anwander
- Institut für Anorganische Chemie Universität Tübingen
- Auf der Morgenstelle 18
- 72076 Tübingen
- Germany
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14
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Summerscales OT, Batista ER, Scott BL, Wilkerson MP, Sutton AD. Reversible Formation of a Cerium‐Bound Terminal Hydride: Ce(C
5
Me
4
SiMe
3
)
2
(H)(thf). Eur J Inorg Chem 2016. [DOI: 10.1002/ejic.201600737] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
| | - Enrique R. Batista
- Theoretical Division Los Alamos National Laboratory 87545 Los Alamos NM USA
| | - Brian L. Scott
- Materials and Physics Applications Division Los Alamos National Laboratory 87545 Los Alamos NM USA
| | | | - Andrew D. Sutton
- Chemistry Division Los Alamos National Laboratory 87545 Los Alamos NM USA
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